Re: Is it possible to graft or splice gymnosperms and angiosperms together?

In the process of grafting, a branch from one species of plant is attached to a plant of another species and induced to grow. It's often used to improve the vigor of fruit trees; it's common practice to graft a branch of a tasty apple species, like Red Delicious, onto a rootstock of a hardy, fast-growing, but not-so-tasty crabapple. When a branch is successfully grafted, it ends up sharing the vascular system of the plant it is grafted onto. Plant vascular systems, unlike our circulatory systems, are fairly simple: the tubelike xylem cells carry water and nutrients from the roots upward, and the phloem cells carry sugar from the leaves, where it is manufactured, to the rest of the plant. Generally, the nutrient requirements of plants are very similar, even among plant groups as different as gymnosperms and angiosperms, so it would be theoretically possible to graft one onto the other.

Most grafting is done by humans, but some parasitic plants can actually graft themselves into their hosts' vascular systems! In fact, among parasitic plants, there are many examples of the exact kind of grafting you mentioned, between a gymnosperm and an angiosperm. The genus Arceuthobium, in the angiosperm family Santalaceae, consists of 42 species that are parasites to conifers (gymnosperms). Here is a good photo of a spruce tree with an Arceuthobium infestation.

In your question, you mention the idea of "creating new species" by grafting gymnosperms and angiosperms. This is an intriguing thought, but unfortunately it would be impossible. In plants (and animals), the cell lines of the body are divided into two categories: somatic cells and germ cells. The somatic cells produce the organism's body and allow it to function in the world, while the germ cells are used in reproduction. Grafting is a process that only involves somatic cells, so any changes produced would not get passed down to the next generation. It would be theoretically possible to graft the germ cells of a gymnosperm onto an angiosperm, or vice versa, but the grafting would not affect the seeds themselves. They would turn out to be only gymnosperms (if the source plant was a gymnosperm) or only angiosperms (if the source plant was an angiosperm). In order for a group of organisms to be considered a species, their unique characteristics must be passed down through generations in their genetic material.